This book introduces young children to the basic ideas of comparing and ordering lengths, weights, time and capacities. Engaging hands-on activities develop these ideas, along with the concept of units of measure and the use of measurement tools. The investigations follow children's natural progression from using many copies of a unit to iterating the unit to using a tool that iterates the unit. The supplemental CD-ROM features interactive electronic activities, master copies of activity pages for students and additional readings for teachers.